Catechism of the Catholic Church

The Psalter is the book in which The Word of God becomes man's prayer. In other books of the Old Testament, "the words proclaim [God's] works and bring to light the mystery they contain." The words of the Psalmist, sung for God, both express and acclaim the Lord's saving works; the same Spirit inspires both God's work and man's response. Christ will unite the two. In him, the psalms continue to teach us how to pray. (2641)